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Beyond “Flood Zones:” Time to Personally Floodproof Homes and Businesses

By Barry Klein -- September 13, 2017

“We’ve had heavy back-to-back rainfalls before. So I don’t think it’s the new normal. When you talk about a 1 percent chance of happening [in a given year], it can happen. You can flip a coin and have it come up heads 10 times in a row. It’s just, statistically, it shouldn’t happen, but it can.”

— Mike Talbot, then Executive Director of the Harris County Flood Control District (2016)

“Floodproofing needs to be routine for Houston area property owners based on their individual perception of risk. Each property owner would consider their elevation in the landscape, distance from nearby bayous and channels that can overflow, and whether their home or business sits on concrete pads or pier-and-beam foundations.”

— Barry Klein (below)

I live in a 100-year old house in Houston. I avoided the recent flood (and those before Hurricane Harvey) thanks to my higher elevation north of Buffalo Bayou and two-foot piers under my house. So not only location, but floodproofing, can be a first line of defense to keep the first responders away.

In the months after Allison, which was called a 500-year flood, brought massive flooding to Houston in 2001, the Harris County Flood Control District released a booklet of more than 30 pages, Off the Charts, to explain to stunned Harris County citizens why their taxes had bought them so little flood protection. It is actually an excellent primer.

On the penultimate page, we find this statement:

“It’s impossible to control the extraordinary forces of nature.”

Since then the county has spent hundreds of millions of dollars more trying to control flooding, or at least reduce the risks of it. But big flood events continue. Some are calling Harvey a thousand-year event. The District is very much under scrutiny.

Mike Talbot’s View

Mike Talbot, quoted above (interview) made several enlightening statements. Since it was published, Talbot has retired from the Harris County Flood Control District. He spoke twice to my group, the Houston Property Rights Association, a talk I remember well.

Talbot, who seems to be a straight-shooter, described a flood protection system based on the so-called 100-year flood event, which can happen often. And he speaks of “extreme rainfall events” that we get occasionally.

So flooding is a given. What Talbot does not make clear is that the risk will vary depending on where you live on the landscape (which is not flat), how close you live to a bayou, and the particular characteristics of an individual storm, which are never predictable.

Talbot notes that developers have to comply with “two inch thick” criteria manuals. So development is not “unchecked”. Of course, sometimes the manuals are not followed. But, in any event, the system is not designed to stop all flooding.

On the Prairies

The following is an important statement from Talbot that needs to be investigated. He implies that the prairies cannot absorb much water. Elsewhere, I have seen him refer to a report by his agency that concluded the clay and sand mixture in our prairie soil does not allow for much absorption:

A lot of the ink that has gone down after [the Tax Day flood] has been given to critics with an agenda. When somebody wants to claim that, “well, it’s because we’re paving over all the wetlands and these magic sponges out in the prairie would have absorbed all that water,” [that’s] absurd.

[During the recent floods], the heaviest rain fell on the prairie, and the prairie did some good, but then it flowed off of the prairie, and all the runoff from the prairie is what flooded that development.

Some people assert that the prairie, once covered with high grass with 10-foot-long roots, would be absorbing the storm waters if it had not been replaced by impervious development. But we have clayey soils in our area. At least one report by settlers traveling inland spoke of walking for days through west Harris County with water to their knees after major rains. So, the absorbent qualities of the Gulf Coast prairie is probably exaggerated.

More Government Planning?

Many people, such as the editorial board at the Houston Chronicle, are pointing to global warming and climate change to argue that higher taxes are needed for expanded infrastructure to accelerate drainage, and that planners should not look just at past flooding to determine flood zones. They argue that local governments need to draw vastly bigger flood zones, in which development would be banned to accommodate the projected bigger, wetter storms.

I personally am dubious that wider, deeper bayous, combined with flood zones designed to accommodate the yet unseen 2,000- or 5,000-year flood (how big are we talking here?), will protect us from flooding. It would all be based on computer modeling, which is subjective and should never be trusted. (The “spaghetti models” shown on TV during the run-ups to Harvey and Irma are evidence of that. Each strand of spaghetti is the product of a team of modelers making hundreds of assumptions which result in different scenarios.)

Floodproofing

In recent months I have decided that floodproofing needs to be routine for Houston area property owners based on their individual perception of risk. Each property owner would consider their elevation in the landscape, distance from nearby bayous and channels that can overflow, and whether their home or business sits on concrete pads or pier-and-beam foundations.

The new routine for gulf coast dwellers would includesealers and waterproof paint, flood bags and flood gates, all combined with back up pumps that can protect from moderate flooding (often times flooding is only a few inches of water). Additionally I am hopeful that temporary exterior structures can be devised that would deal with hydrostatic and hydrodynamic pressure on windows and exterior walls of homes when water gets above the level of a foot or two. Renters can look for units above the ground floor and may have to pay a premium for the extra measure of safety. Flood insurance too should be part of everyone’s plan.

The flood control district can help people decide their level of risk by erecting poles around the county showing the level of flooding in our landmark storms. I have it on good authority that The Clear Lake area had such a pole a few years ago until members of the real estate industry succeeded in having it removed.

A few county buildings downtown were flooded by Harvey. Why did the county not use its superior knowledge of the risks of flooding to take extra precautions, such as having more “submarine doors” in the tunnel system to contain the flooding? I recently walked several of those tunnels and found only one such door, which surprised me. The Med Center has them, as well as other kinds of flood barriers now, and so do many commercial buildings in the downtown.

>>>THE THE SITUATION FROM SOMEONE WHO HOME WAS FLOODED 2 YEARS IN A ROW.
THE CORP OF ENGINEERS W/ THE BLESSING OF HARRIS COUNTY HAVE DESTROYED THE LIVELIHOOD OF ABOUT A 1.000.000 HOME OWNERS IN HARRIS COUNTY ALL BC THE CORP OF ENGINEERS BELIEVE THEY CAN MANAGE ALL FLOOD WATER W/ THE USE OF RESERVOIRS…………THIS IS MADNESS ON A SCALE NOT SEEN ANYWHERE ELSE IN THIS COUNTRY, OTHERWISE THERE WOULD BE RESERVOIRS IN EVERY MAJOR CITY TO CONTROL FLOOD WATERS, THIS SYSTEM HAS BEEN IMPLICATED SINCE THE 1940’S W/O ANY MAJOR IMPROVEMENTS. THE SCALE OF CONSTRUCTION GOING ON ALL OVER THIS CITY OF HOUSTON DISPLACES RAIN WATERS WHICH THE RESERVOIR CAN’T HANDLE. THE CORP OF ENGINEERS WAS RESPONSIBLE FOR THE FLOODING IN NEW ORLEANS DURING KATRINA & THEY ARE KEEPING PACE BY FLOODING HARRIS COUNTY & NO ONE IS EVEN BEING CONSIDERED FOR CRIMINAL CHARGES. SINCE WHEN CAN THE CITY OF HOUSTON DAMAGE PERSONAL PROPERTY AT THIS SCALE & NOT BE CRIMINALLY CHARGE W/ NEGLIGENCE. NO GOV. AGENCY CAN HANDLE FLOOD WATERS & WHO IN THEIR RIGHT MIND WOULD EVEN TRY, THIS IS INSANE, THIS IS CRIMINAL & SOMETHING NEEDS TO BE DONE ABOUT THIS. THE NEGLECT ON THE RESERVOIR, RIVERS, BAYOUS IS ON HARRIS COUNTY & THEIR EXCUSE EVERY YEAR IS WE DON’T HAVE THE MONEY. SOME 15 YRS. OR SO AGO WE BUILT NEW HIGHWAYS & THERE WAS A CONSIDERATION OF BUILDING A HUGE STORM DRAIN UNDER THE FREEWAY ~ I-45 -I-10 TAKING ALL FLOOD WATERS TO THE GULF OF MEXICO, THIS WAS DENIED BC IT WOULD HAVE SLOWED PRODUCTION OF THE FREEWAY, OPPORTUNITIES TO CORRECT THE FLOODING IN HARRIS COUNTY WERE CONSIDERED BUT DENIED LEAVING OVER A 1,000,000 FLOODED. THESE BASTARDS EVEN NOW DENY THEY ARE DOING ANYTHING WRONG ~ HARRIS COUNTY & THE CORP OF ENGINEERS IS LIABLE FOR ALL DAMAGES, LIFE-THREATENING SITUATION, STRESS, PTSD, INJURIES, DEATHS…………I HOPE SOMEONE OUT THERE IS LISTENING!!!

I live well within the bounds of the Katy Prairie. Anecdotally, I’m in agreement with Mr. Talbot’s assessment. When planting trees, I frequently encounter impermeable clay. It absorbs no water after many hours of water sitting on it. It may as well be rock. I literally have to shave the surface ¼ inch at a time with a shovel to make progress.

People don’t think three dimensionally. (me included) When purchasing/building a home they are usually concerned about how close they are to a creek/bayou. The flood maps are also two dimensional which doesn’t help things. The flood maps can be very wrong as well. According to the flood map for Harris County, most of my neighborhood should have flooded. (none of it did because the developer, one who still lives in the neighborhood, wasn’t cheap)

People also don’t understand the purpose of artificial lakes. Those are put in to retain the water that would normally be absorbed by the property once the property is paved. They are not there to prevent your house from flooding. They are put there to avoid flooding your neighbor worse than before. This is sort of like the fire department which is really there to save your neighbor’s house. Your burning house will likely be a total loss. If you manage to avoid flooding where there are artificial lakes in your neighborhood it is because they used the dirt dug out of the lakes to raise the level of the land your house sits on.

This city is doomed. Too many people live here. The politicians say perpetually that the human species will continue to expand in population. Its as though they want more and more babies being made. The politicians say that Texas has plenty of room for more people. Nobody ever stopped to properly assess the soil (clay). Cracked foundations are the immediate result. Harris County Soil type has been known since the 1930’s!! That didnt change development! In longer term effects, it does not soak up water. Land is flat. Whoever thought about digging out and terracing or sculpting this land? Too late now.

iJudith Ann … My understanding is that, If the flood bags, which are latter day sandbags, and flood gates at the doors, are imperfect seals and allow water to leak in, the water can be pumped out before it accumulates, limiting damage.

The mention in this article that the prairie around Houston does not absorb the rainfall is verified in the historical accounts of travelers on the San Felipe Road in the first decades of Houston’s existence. The prairie lying south of Buffalo Bayou, especially in the area of Piney Point, was flooded by rain that ponded to create a large area of water about 8 inches deep. The prairie soil did not absorb the water, but it was impermeable. Two historical accounts of prairie flooding are provided below.

“The following morning we paid half a dollar each for our overnight stay, saddled our horses and continued over the boggy Houston Prairie. The horses sank deep into the mud and water… Despite our host’s admonitions, we continued our journey in the afternoon. We hoped to cross, or at least reach, the heavily swollen Buffalo Bayou which was three miles away… We continued on the right side of the river following the wagon tracks. The prairie being under water, only the tips of the grass peeked out. Where the wagon wheels had traveled they knocked the grass down leaving behind a distinct trail. On each side of the trail were swamps.”

An entry in the diary of Miles Squier Bennet, who was en route from Houston to San Antonio with supplies for the Texas army:

“Sat Feb 2 [1838]. I started from Hd. Qrs. With a Lieut. Some soldiers and wagons with supplies for the post at San Antonio, wintry weather, delayed at Mrs. Wheaton’s at the crossing of Buffalo Bayou first by high water, then by a heavy sleet which broke a great deal of timber. The bayou and prairie were flooded, I had some adventures killing wild game and exploring for a practicable route. Was constrained to diverge from our road and cross the Brazos at Richmond.”

Maybe those travelers passing through the prairie were wading through water because they were wading through WETLANDS? Those would be prairie wetlands, and they hold back, slow down, absorb, and filter water. The Katy prairie was not and is not like somebody’s unmowed front yard, although weedy front yards are not bad for slowing runoff either.

Nobody claims that rainwater sinks instantly into our prairie soils. But neither does it run off in torrents like it does from our paved and built city, carrying all the pollutants washed off our roads and parking lots and yards. Instead the prairie’s deep-rooted tall grasses convey the stored water into the ground, replenishing our ground water. The Katy Prairie Conservancy estimates that one acre of tallgrass prairie can store up to 400,000 gallons of water.

But wetlands are wetlands, sometimes perennial like ponds and sometimes intermittent, like bogs and marshes, and it’s best to avoid wading through wetlands unless you’re properly attired. And best to avoid building on top of them also.

If you look in small towns, in the older areas, there are many old homes that have survived many storms and floods. They are all built on pier and beam foundations and breath. The additional 2 to 3 feet of elevation and the ability of the water to run underneath the house allows them to escape being flooded in most cases. If flooded, they dry out faster.

We COULD have Israeli-style steel & concrete houses, if so many were not invested in the crap (often import) of Ho’de Po’ & Lo’-styled water soluble stuff nailed on a thin slab. There are many improvement options, as Barry said, beams and posts. Think of the houses on stilts, along the coast.
How many will still be here, year after year without insurance (exactly as in the Caribbean), then repeatedly needing non-general welfare?
I’m in Victoria, where the gov says we’re in a flood zone, though it’s never been flooded. But that helps them protect their positions? I agree each property owner must carefully consider; yet, the majority of folks are NOT owners. Rental property keepers are mostly concerned only with short-term profits. Low-income housing is all always full, with years’ waiting lists. But it’s not profit able to build THAT, nor gasoline refineries. The things not highly profitable will be ignored. And there’s nothing We The Poor People can do about that, unwilling to riot.

Excellent commentary on the Harvey flooding. As many here note, the mythical “absorption” of natural prairie is minimal at best once a few inches of surface is saturated. “Wetlands” do hold water but they are nearly always downstream of water flows and are permanently flooded at least partly. Since they are already saturated at surface level, unless they are surrounded by high berms or steep walls, heavy rains simply overflow swamps and bogs and water flows downstream. They don’t stop flooding.
Two to four feet of rain within three days will flood nearly everywhere that occurs, Houston or otherwise. If there were steep hills or mountains, existing rivers, streams etc. would all overflow and flood. We see that in West Virginia. What can be done?
Barry suggests elevating structures and pier and beams. Good thoughts for places that flood. Recall that streets are intentionally part of existing flood control. They are supposed to temporarily hold water during heavy rains. It is when they exceed capacity that home/apt flooding occurs. The Criminal Courts buildings were not badly flooded but short sighted design by expensive architects neglected the issue of sewer backups during extreme floods. That was stupid and is correctable.
Clearly, homes, etc. near flooded bayous will not all be rebuilt and shouldn’t be. Places that can be remediated w/ elevation can be rebuilt. New parks can be created from bought out unsalvageable homes and structures. Upstream reservoirs/parks should be considered to limit flood flow into Addicks and Barker reservoirs.
Now the problems are clearer. The solutions are also.

I think it is past time for the HAARP, High Frequency Active Aurora Program, to be investigated.
Senator Ted Stevens of AK helped to start it. If we are spending millions there why can’t we know what they are really doing?

The mosquito spray being used in the Houston area is made by Monsanto and is very dangerous and not allowed in the European Union. Who made this deal with Monsanto? Off with their heads!